Liquid filtration membranes for blood purification and separation of biological products may be in hollow fiber or flat sheet configurations and have good biocompatibility and hemocompatibility. Polysulfones, a class of engineering thermoplastic, have been widely used in membranes for hemodialysis and protein separations. Polysulfones have high glass transition temperature, good mechanical strength, and excellent chemical resistance, rendering them ideal materials for membrane applications. Despite these benefits, the hydrophobic nature of polysulfones made them less ideal in these aqueous applications such as hemodialysis and protein separation. The hydrophobicity often results in fouling when applied to biological materials, resulting in reduced efficiency due to flux decline, high cleaning and maintenance costs and low membrane lifetimes.
As a result, a blend of polysulfones together with a hydrophilizing agent, for example polyvinylpyrrolidone (PVP), may be used to achieve better biocompatibility and hydrophilicity. However, PVP is water-soluble and is slowly leached from the porous polymer matrix creating product variability. Thus, hydrophilic porous membranes possessing excellent thermal, mechanical properties and improved fouling resistance are desired for longer service lifetimes.